Here I will be sharing my top 10 methods for arrays in js.
push( element )
pop( )
indexOf( element, initial index )
at( index )
forEach( callbackFunction )
includes ( element )
toString ( )
flat( nestingLimits )
concat( …element, …element, etc.. )
reverse()
push ( element
)
Push method adds element in the end of the array.
const nums = [1, 3, 5];
console.log(nums); // output : [1, 3, 5]
nums.push(7);
console.log(nums); // output : [1, 3, 5, 7]
pop ()
Pop removes the element from the end of the array and also returns that removed element.
const nums = [1, 2, 3, 4, 5];
console.log(nums); // output : [1, 2, 3, 4, 5]
let removedValue = nums.pop();
console.log(removedValue); // output : 5
console.log(nums); // output : [1, 2, 3, 4]
indexOf ( element
, initial index
)
It searches the element in the array and returns the index of that element. Using this method we can also set the initial index from that the element to be searched.
// indexOf(element, initial index)
const nums = [1, 2, 3, 4, 5];
console.log(nums); // output : [1, 2, 3, 4, 5]
// Searching element without initial index
console.log(nums.indexOf(2)); // output : 1
// Searching element with initial index
console.log(nums.indexOf(5, 2)); // output : 4
console.log(nums.indexOf(1, 3)); // output : -1
at ( index
)
It returns the element present on the index if found. This method accepts both positive indexing (0 to length - 1 ) and negative indexing (-length to -1 ).
const nums = [1, 2, 3, 4, 5];
console.log(nums); // output : [1, 2, 3, 4, 5]
// Positive indexing => 0, .....(Array.length - 1)
console.log(nums.at(2)); // output : 3
console.log(nums.at(6)); // output : undefined
// Negative indexing => -(Array.length), ........ -1,
console.log(nums.at(-5)); // output : 1
console.log(nums.at(-6)); // output : undefined
forEach( callbackfun(value, index, Array)
)
With this method, we can iterate through the arrays and access each element seprately.
const nums = [1, 2, 3, 4, 5];
console.log(nums); // output : [1, 2, 3, 4, 5]
/* In this iteration we are only accessing values
so we don't have to write index and Array. */
nums.forEach((element) => {
console.log(element);
})
/* output :
1
2
3
4
5
*/
includes ( element
, initial index
)
It searches the element in the array and returns true if found otherwise false. It doesn't return the index like indexOf()
method.
const nums = [1, 2, 3, 4, 5];
console.log(nums); // output : [1, 2, 3, 4, 5]
// Searching element without initial index
console.log(nums.includes(2)); // output : true
// Searching element with initial index
console.log(nums.includes(5, 2)); // output : true
console.log(nums.includes(1, 3)); /*// output : false => after index 3
not a single 1 is present. */
toString ( )
This method creates a new string from the Array and return the string. It doesn't manipulates the original Array.
const nums = [1, 2, 3, 4, 5];
console.log(nums); // output : [1, 2, 3, 4, 5]
// take temp to store the converted string
const temp = nums.toString();
console.log(temp); // output : 1,2,3,4,5
console.log(typeof temp); // output : string
// Checking original array
console.log(nums); // output : [1, 2, 3, 4, 5]
flat ( depth
)
This method removes the depth in the array and creates a new array. It doesn't manipulate the original array.
const nums = [1, [2, 3, [4, 5]]]; // Highest depth : 2
console.log(nums); // output : [ 1, [ 2, 3, [ 4, 5 ] ] ]
console.log(nums.flat(1)); // output : [ 1, 2, 3, [ 4, 5 ] ]
console.log(nums.flat(2)); // output : [ 1, 2, 3, 4, 5 ]
// Checking original Array
console.log(nums); // output : [ 1, [ 2, 3, [ 4, 5 ] ] ]
concat ( …value1, …value2, …etc
)
This method joins all arrays and returns a new array. It doesn't manipulate the original array.
const nums1 = [1, 2, 3];
const nums2 = [4, 5, 6];
const nums3 = [7, 8, 9];
console.log(nums1, nums2, nums3); //output : [ 1, 2, 3 ] [ 4, 5, 6 ] [ 7, 8, 9 ]
// Joining all arrays in single array
const temp = nums1.concat(...nums2, ...nums3);
console.log(temp); // output : [1, 2, 3, 4, 5, 6, 7, 8, 9]
reverse ( )
This method changes the order of the order of the element in the array and also changes the original array.
const nums = [1, 2, 3, 4, 5, 6, 7, 8, 9];
console.log(nums); //outptut : [1, 2, 3, 4, 5, 6, 7, 8, 9]
nums.reverse();
console.log(nums); // output : [9, 8, 7, 6, 5, 4, 3, 2, 1]
So this was my top 10 methods for array in JavaScript. I know that I haven’t added map, filter and reduce for my personal reasons.